1. Field of the Invention
The present invention relates to a light-receiving unit for an optical mouse, and more particularly, to a light-receiving unit for an optical mouse in which lead frames and an optical sensor are integrally molded with transparent resin.
2. Description of the Prior Art
In general, an optical mouse is designed to detect movement of an image carried in light reflected from a mouse pad having the image thereon and received therein, thereby causing a cursor on an associated display screen to be moved in accordance with the movement of the mouse, and to enable several functional signals to be inputted to a computer system by clicking of buttons equipped thereon, separately from a keyboard unit.
Since such an optical mouse has advantages of the accuracy of its motion detection, and smoothness in its motion, as compared with the prior art ball-type mouse, its use is gradually increasing.
An optical mouse is adapted to cause a cursor on a display screen to be moved, by optically detecting its own motion, converting the detected value to an electrical signal, and sending the signal to a computer.
Referring to FIG. 1, there is shown a typical optical mouse. Such an optical mouse 10 comprises a light source 12 for emitting light into a casing 11, a light-receiving unit for detecting an image formed on a mouse pad due to the light emitted thereto, an operating unit for converting the signal detected by the light-receiving unit to an electrical signal and then sending the signal to a computer, and buttons 18 for clicking by a user. In general, the light source 12 includes a high luminance LED for irradiating a bright light to a pad surface.
The light-receiving unit comprises a lens 13 for converging light emitted from the light source 12 and reflected from the mouse pad/contacting surface and carrying an image formed on the surface, an optical sensor array 16 for detecting movement of the converged image, and lead frames 19 adapted to be electrically connected between the optical sensor array 16 and a printed circuit board 14 and to support the optical sensor 16.
The prior art optical mouse has been fabricated in such a way that an integrated circuit chip 15 having the optical sensor array 16 therein is made into a package type and then built in a case, and the case is mounted on the printed circuit board 14.
FIG. 2 shows a conventional light-receiving unit for an optical mouse. As shown in the drawing, in a fabricating operation of a conventional light-receiving unit for an optical mouse, an integrated circuit chip 150 having an optical sensor 160 is bonded to lead frames 170 by using a wire bonding procedure, and then transparent resin 190 is applied thereto. The integrated circuit chip applied with the resin is covered with a cap 180 having a slit 181 for allowing a converged image to be passed therethrough, resulting in a full package type integrated circuit chip. The full package type IC chip is mounted on a printed circuit board 100.
As again shown in FIG. 2, in a configuration of the light-receiving unit wherein IC chip package is mounted on the printed circuit board 100, the IC chip 150 is disposed over the printed circuit board 100 and electrically connected thereto by means of the lead frames 170. The printed circuit board 100 is formed with an optical guide 101 for guiding an image formed on a mouse pad. A lens 130 adapted to converge the image is positioned in a light path under the light guide 101.
The above-mentioned conventional light-receiving unit for an optical mouse has disadvantages in that a full package type IC chip must be mounted on a printed circuit board in order to connect the printed circuit board to the IC chip, and a case for protecting the full package type IC chip must be prepared, thereby increasing its manufacturing cost and lowering its productivity.
Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a light-receiving unit for an optical mouse which is integrally fabricated by molding lead frames and an optical sensor with transparent resin.
It is another object of the invention to provide a light-receiving unit for an optical mouse which is simplified by integration of the associated components, is improved in manufacturing efficiency, and is lowered in manufacturing cost.
It is a further object of the invention to provide a light-receiving unit for an optical mouse which is reduced in the number of its components such as a cap, a lens, etc. by integrating lead frames, an optical sensor or a lens into a molding package, thereby decreasing mold cost and improving productivity.
In order to accomplish the above object, the present invention provides a light-receiving unit for an optical mouse comprising: a lens for converging light, which is emitted from a light source and then reflected from a contacting object, in which the light carries an image formed on the contacting object; a printed circuit board having a light hole for allowing the light converged by the lens to be passed therethrough; and a molding package made by molding lead frames electrically connected to the printed circuit board and an optical sensor bonded to the lead frames with transparent resin, which is adapted to detect the image carried in the converged light.
The present invention also provides a light-receiving unit for an optical mouse comprising: a printed circuit board having a light hole for allowing converging light, which is emitted from a light source and then reflected from a contacting object, to be passed therethrough, in which the light carrys an image formed on the contacting object; and a molding package made by molding lead frame electrically connected to the printed circuit board and an optical sensor bonded to the lead frames and adapted to detect the image carried in the converged light with transparent resin; wherein the transparent resin is provided at its bottom surface with a slit/lens area for allowing the converged light to be passed therethrough and a mask area for preventing the converged light from passing therethrough.